Thiamine-binding lipoprotein (Cypl) and related proteins are specific to Mycoplasma species [1]. Cypl, also known as p37, whose gene is part of an operon encoding two additional proteins, which are highly similar to components of the periplasmic binding-protein-dependent transport systems of Gram-negative bacteria. It has been suggested that p37 is part of a homologous, high-affinity transport system in Mycoplasma hyorhinis, a Gram-positive bacterium [1]. Its structure indicates that it is a thiamine pyrophosphate-binding protein [2]. The monomer is a mixed alpha/beta fold split into two globular domains (domains I and II) connected by two linker regions and the C-terminal helix.

1: A mycoplasma high-affinity transport system and the in vitro invasiveness of mouse sarcoma cells. Dudler R, Schmidhauser C, Parish RW, Wettenhall RE, Schmidt T; EMBO J 1988;7:3963-3970. PMID:3208756

2: Structural insights into the extracytoplasmic thiamine-binding lipoprotein p37 of Mycoplasma hyorhinis. Sippel KH, Robbins AH, Reutzel R, Boehlein SK, Namiki K, Goodison S, Agbandje-McKenna M, Rosser CJ, McKenna R; J Bacteriol. 2009;191:2585-2592. PMID:19233924